"So you could almost guess that the grandparents are helping their own children to stay in the general area by looking after the grandchildren while their children go back to work to pay the mortgage."

Some grandparents say they feel exploited by their busy adult children, but simply cannot say no.

"If we talk to grandparents they will always say, 'look, my children need it, my grandchildren need it, I will be there, come hell or high water'," Mr Day said.

"They are giving up their time freely and happily.

"As an aside they may very well say to us 'but geez, it'd be nice sometimes if somebody said thank you'."

Lakshmi Murthy and her husband are happily and comfortably retired and look after their two granddaughters five days a week.

"Time goes really, really fast," Ms Murthy said.

"I take her to the local library here. She plays with other children and all that, we come home and then we have lunch and then a sleep.